Had no problems with my pond until my partner accidentally ripped the lining and we brought in a company to drain it refill it and patch it in October 2020. Immediately bought 4 oxygenating plants in October. Water looked clear. Frogs came in Feb-March so far no obvious problems. Still clear. Bought 3 new plants a month ago one marginal and 2 deep including water lily. A few weeks ago I thought there was a lot of bubbles on the water surface. Today more bubbles and noticed a thick brown slime covering my liner below the surface. There does seem to be some loose green algae strands too. I really don’t have a clue what I’ve done to cause this and how I can get rid of it. Please any thoughts!